Electric switch



Jan; 22, 1929.

J. S. BAKER ELECTRIC swn'cn 2 Sheets-Sheet Filed Oct; 25. 1922 Jan. 22, 1929.

1,699,517 J. 5. BAKER ELECTRIC SWITCH Filed oct. 23. 1922 2 Sheets-Sheet 2 I Many electrical devices,

, 30 the electriccircuit aft A 7 cause of. abnormal heat conditions, is not Patented Jan. 22, 1929.

- ult mo-{STAT S PATENT F .romr s. mum,

or CHICAGO, ILLINOISyASSIGNOB. fro THE 0001: ELECTRTCHGOMPANY, or cnIcneo, ILLINOISXA CORPORATION or ILLINOIS.

ELECTRIC swI'rcH.

"Application filed October 23, 1922. Serial No. 596,225.

My invention relates to electric switches and it has special referenceto protectiveswitches that are-automatically releasable to I open an, associated electric circuit when abnormal heat conditions obtaintherein. "More particularly my invention pertains to electric switches of the aforesaid char- 1 ,acter that are adapted to be restored to operative condition after the abnormal heat conditions, causing release of the switch, have discontinued, making it safe to permit again the flow of electric cunt in the circuit;

electrical heating devices such as flat irons, cookers and the like,

are liable to become overheated because of neglect to'turn oil the electric currenfafter the devices have been .used or for other numerous reasons. The overheating of electricaldevicesand those particularly used for household purposes frequently'causes .the devices-themselves to burn up besides scorching or, setting fire to adjacent materials. 7

'An obj ct, therefore, of my inventionyis to provide an electric switch which will be automatically opened when abnormal heat conditions or temperatures obtaininthe apparatus to which my switch lis applied. Moreover, by means of my gesent invention,

, ing opened belikely to be closed through the agenc of my switch .until the excess heat has en dissipated which then allows my switch to be restored to operative condition. I

Another object ofmy invention is to provide a resoldering switch that is capable of being manually reset to closethe electric circuit only whenthe abnormal heat obtaining in the associated electrical device has become dissipated we point where'the re-,

soldering holding-in element becomes frozen -temperature obtaining in the; heating element. -Since my switch is maintained in.

operative condition only when the resoldering or fusible element is frozen or in normal condition, it is quite obvious that-my, switch and particularly of my invention;

A handle 13' is sup can not be reset to close the circuit through the'associated electrical device unless it is cooled below the danger point. r

Another object of my invention is to provide a switch of the foregoing character which will be simpleand economical to construct and eflicient in operation.

Other objects and novel features of my invention will be hereinafter pointed out, and for a better understanding thereof, reference may be had to the following description and the accompanying drawings, in which- Figure 1 is a view in elevation of an electrical device, such as a flat-iron equi ped with an electric switch embodying a form Fig. 2 is a view in elevation of a form of my proved electric switch having its cover plate removed to expose the internal mecha nism thereofin on-position;

:Fig. 3 is a view similar to Fig. 2 excepting that themechanism is shown as occupying ofl.-position I Y V Fig. 4 is a'plan view of the electric switch of Figs, 2 and 3;

Fig. 5-is a view partially in'elevation and partially in section taken approximately along the line 5-5 of Fig. 2 and showing in i eptitin aportion of the electric iron of Ig. r Fig. 6 is a view taken approximately along theline66ofFig.'2; A f

Fig. 7 is a detail view showing/a heat responsive or fusible element that may be comprised'in my switch mechanism; and

Fig. 8 is a view showing the contact members of the electrical device of Fig. 1.

For convenience, I have illustrated in Fig. 1 an electric flat-iron 10 which is provided with a usual plug, connector 11 that serves to connect the current-conductingleads 12 tothev heating element of the flat-iron 10. orted upon a member 14 secured to the flat-iron 10 by means of'screw bolts 15.. .An opposed push button electric switch 16. is mounted upon the spring support 14 immediately adjacent to the plu connector 11. It is to be understood that the electric switch 16 is independent of the plug connector 11 and is connected in circuit intermediate the" plug connector 11 and the heating elementof the iron 10.

The electricswitch 16, as shown'in Figs.

"2, El -and 4', is provided with two opposed push buttons 17 and 18 that are severally positioned on each side of the handle support 14 of the flat-iron 10. In this manner, the electrical switch 16 may be manually actuated with great convenience without removing the hand from the handle 13. The switch of Fig.2 shows the opposed push buttons occupying their on-position, and Fig. 3 shows them occupying oif-position.

The opposed push buttons 17 and 18 project through insulating members 19 and 20, respectively, that are mounted upon the easing 21 whichhouses the switch mechanism. When the cover plate is applied to'the mechanism of Fig. 2, the electric switch is completely housed, this cover plate being secured to the switch casing 21 by means of screws that may be threadedjinto the holes 22.

The push buttons 17 and 18 are oppositely secured to a central cross-piece 23 which is adapted to slide to and fro in accordance with the actuation of the push buttons. A guide plate 24 is positioned behind the cross-piece 23 and is provided with upstanding lugs 25 and 26 that project through openings 27 and 28, respectively, formed in the cross-piece 23.- The guide plate 24 is also provided with spaced upstanding lugs 29 and 30 formed at its lower portion. The guide plate 24 is, therefore, supported upon the cross-piece 23 by means of the lugs 25 and 26 and in addition is adapted to move in conjunction therewith. Ahelical spring 31 is positioned intermediate the upstanding lugs'25 and 26 and the upstanding lugs 29and 30, and is secured at its lower end 32 to a latching member 33 and at its upper end as shown in Figure 5 to an eyelet 34 formed on the cross-piece bridging the two portions of a rocker-arm 35. The spring 31 constitutes an ofi-and-on center spring and is adapted to oscillate the rocker-arm 35, which is pivoted upon ears 36 and 37,,that are struck up from a supporting bracket 38 integrally formed on a rear supporting plate 39. An electrical contact member 40 in the form of a sectional cylinder is mounted upon the rocker-arm 35 but is insulated therefrom by means of a mica cylinder'43.

The latch 33 is provided with an ear 33 that projects through a slit 42 formed in the lower portion of a floating lever 44 that is provided at its upper end with two projections 45 and 46 that extend through openings as-at 47 ,-formed in a stationary supporting member 49, as shown 1 particularly in Figs. 4 and 5. The latch 33 is normally adapted to engage teeth 50 formed upon a heat responsive element 51 that is soldered to a cylindrical pin 53 (see Fig. 7) secured to the rear plate 39. v

The heat responsive element 51, as shown in Fig. 7 constitutes a cylindrical rotatable member 52 upon the exterior of which the teeth 50 are formed. The threaded pin 53. serves as a support for the cylindrical member 52 and is secured thereto by meanslof a fusible or soldered connection 54. As long as the soldered connection 54maintains its solid state or is'frozen', the cylindrical member 52 is held against rotation upon the pin 53. However, when the connection 54 becomes liquefied or the soldersoftens, the cylindrical member 52 is then free to rotate upon the pin 53.

The contact member 40, mounted upon the oscillating rocker-arm 35 is adapted to engage a cooperating spring contact member 55 that is shown in Fig. 4 as extending transversely of the switch mechanism and connected to a conducting member 56 by means of a screw 57. The electrical contact member 40 is also adapted to engage a second and adjacent stationary spring contact member 58 that is secured to a conducting member 59 by -means of a screw 60. As shown in Figs. 4 and 5 the contact member 40 is adapted to bridge the space between the stationary contact members 55 and 58 of myelectric switch and when in the position shown in Fig. 2, serves to bridge the contact members 55 and 58 and thereby connects the conducting member 56 to the conducting member 59. When the contact member 40 occupies the position shown in Fig. 3, the contact members 55 and 58 are disconnected from each other and the electric circuit through the switch is broken.

As shown in Figs. 4 and 5, the contact member 55 is connected to the conducting member 56 that is insulated from the rear plate 39 by means of interposed insulating material 61.

sulated from the rear plate 39 but spaced from the conductor 56, as shown in'Figs. 2 and 3. An insulating member 61 serves to insulate the conductors 56 and 59 at their rear. The conductor 59 is connected by means of a connector 62 to one terminal 63 of a heating element 64 which is embedded in the body 65 of the flat-iron. The other conductor 66 of the heating element is connected by means of a connector67, as shown in Fig. 8, to one of the terminals 68 of the fiat-iron. The conductor 56 of the electricswitch is connected in any suitable manner, preferably such as a strap 69 to another terminal 7 O of the flat-iron.

It will thus be observed that the conduc- 59 and, is, therefore, in very close thermal relation to the heating elementof the flatiron. Moreover, the heat responsive elcment 51, in addition-to being in heat conductive relation to the, heating element .of

' the flat-iron, is also in very close convective relation to the flat i'ron by reason. of its being located in the lower portion of the electric switch'16.,

The plug connector 11 is adapted to enj gage t e contact members 68 and. 70 of Fig. 8..

From the foregoing description, it will be observed that'the electric sw'itch'of my vention is interposed in the electric circuit intermediate the plug connector 11 and the heating element 64 of theflat-iron and, thereore, is operative to open-or close the electrical circuit in response to the action of the heat responsive element 51.

-- en my electric switch is applied to. a

heating device, such as the flat-iron 10 of Fig. 1, the heat responsive element 51 which,

" 1n this'instance, is shown as being a selfsoldering device and comprising a" rotatable ratchet .wheel 52 is in close thermal relation to'the heating element .64 of theiron. Should the temperature of the heatingv element be soldered connection 54' come excessive the will'liquefy, thereby permitting the ratchet *wheel 52 to rotate relativeto the pin 53. In

- When the'rocker-arm isinjthis this circumstance, the latch'33. is released and the floating lever 44 is movede'from the position it occupies in Fig. 2 to the position it occupies in Fig. 3. Simultaneously therewith the ofiF-and-on center spring 31 is moved and whenit-passes the pivotal center of the rockersarm'35, the rocker-arnr 35,will

be moved to open position, as shown in position the contact member 40.has interrupted the electric circuit between the stationary contact members 55 and 58. As a result, the

electrical circuit through the iron 10 is im mediately interrupted Operation of the opj posed pushibuttons 17 and 18 will'cause the floating lever 44 to oscillate, but the latch 33 willnot be retained by the teeth on the ratchet wheel=52 of the heat responsive element .51 the 4 soldered connection 54 has, inx'the meantime, b'ecomesolidified. Of course, thesoldered connection 54 will "not solidifyjguntil, the temperature thereof v has been lowered below 'th By*varyingthecomposition of the solderedconnection 54, the temperature at which "it e danger point.

I will liquefy may be regulated. in the event that the soldered connection 54 has soliditied, actuation of the opposed .push buttons 17 and-18: willbauseithe latch 33 to engage sition, shown the ratchet wheel 52 and permit relocation 6f;

the floating rlever 2. .4v to ,-,onposi tion which it en the ifloat gg" Iever'44occupies the po.-. i ljpon; the rocker-arm- 35, {ito ,openj the elec in operative position wheiebysaid electrical -'cone. e, members 55 and 58 at will. In this condition, the electrical contact 40 acts as in. any other electric switch.

When the floating lever 44 occupies the position shown in Fig, 3, the latch member 33 7Q is precluded from disengaging therefrom by reason of the-slot through which the latch 33 projects, being so proportioned that the latch can not be drawn through the opening when'positioned longitudinally of the float- 7 ing lever 44; v I v 'VV hile I have shown. and described in detail one embodiment of my invention, it is I to be understood that many modifications may be made therein without departing from 30 the. spirit and scope of the appended claims.

at I claim as new and desire to secure by Letters 'Patentof the U. S; is

1. An electrie' switch comprising a mov-\ able contact member, an off-and-on center spring connected thereto atone ofits ends for positioning said contactmember either in on-position'br off-position, a latch-connectedto the other end of said spring for normally holding it under tension, and a fusible element normally holding said latch springis retained under tension, said fusible element when abnormally heated releasing the tension in said spring thereof thereby permitting said spring to movesaid contact mem ber of offosition,

'2. An e ectric switch comprising a movable contact member an otf-and-on center spring connectd t to for positio'ning said f contact member either in on-position or oil'- 'p0sition,-aj latch connected directly to and carried by said spring normally holding it under tension, and heat, responsive means normally holding said latch in operative, po-

sition whereby said spring is retained under 7 tension, said heat responsive-means when raised to .an abnormal temperature releas ingthe'tension in said spring thereby permitting the automatic moving of said co ntact member to off-position. 3. An electric switch, comprising a movable cont'actrn'ember, an ofi and-on center spring connected thereto at one of its ends for positioning said .cont act'membereither in Qn-posi'tion or off-position, a latch connected tothe'other end of'said spring .normally holding it under tension, and heat re spon'sive means for controlling the position of said latch and the consequent degree of 9' tension in said spri1 1g.-

4. An electric switch comprislng a movable contact member, an oif-and-on center spring connected thereto at'one endfor positioningv sa1d contact member either in 'on-position or ofisposition, a latch connected tosaid spring at its other end, and heat responsive means which when subjected 'to 1 normal temperatures'holds said latch in position'toexert tension on said spring for 9 holding said contact member in either onposition or off-position and when subjected to abnormally high temperatures causes said latch to release the tension insaid spring whereby the said contact member is precluded from occupying on-position.

5. An electric switch comprising a movabl'e contact member, an on-and-olf center spring connected thereto for positioning said contact membereither in on-position or offposition, and resoldering means normally exerting tension on said spring when said contactmember is either in on-position or off-position, said resolderingmeans when.

normally movable into on-and-ofi positions by actuating said push buttons, and heat responsive means controlling the normal operation of said contact member into on-andofl' positions through the agency of said push buttons, said heat responsive means when abnormally heated permitting of the automatic moving of said contact member to olf-position.

8. An electrical snap switch comprising opposed push buttons, a contact member normally movable into on-and-off positions by actuating said push buttons, and heat responsive means controlling the normal op eration of said contact member into. on-andofi positions through the agency of said push buttons, said heat responsive means when abnormally heated permitting of the automatic moving of said contact member to off-position independently of any movement of said opposed push buttons.

9. An electrical snap switch comprising opposed push buttons, a contact member normally movable into on-and-ofi' positions by actuating said push buttons, and heat responsive means controlling the normal operation of said contact member into on-and- 011' positions through the agency of said push buttons, said heat responsive means when abnormally heated permitting of the automatic moving of said contact member to ofli position and automatically releasing it from operative connection with said push buttons until normal temperature conditions are restored in said heat responsive means.

10. An electrical snap switch comprising opposed push buttons, a contact member when abnormally heated permitting of the automatic moving of said contact member to off-position and precluding the resetting of said contact member into on-position until the temperature of the heat responsive means is restored to normal.

11. An electrical snap switch comprising opposed push buttons, 2. contact member normallymovable into on-and-ofi positions by actuating said push buttons, and heat responsive means controlling the normal operation of said contact member into on-and-ofl' position through the agency of said push buttons, said heat responsive means when abnormally heated permitting of the automatic moving of said contact member to ofiposition and precluding the resetting of said contact member into on-position through movements of said push buttons until the temperature of said heat responsive means is restored to normal.

12. An electrical snap switch comprising opposed push buttons, a contact member normally movable into on-and-ofi' positions by actuating said push buttons, and a fusible element controlling the normal operation of said contact member into on-and-olf positions through the agency of said push buttons, said fusible element when having' an abnormally high temperature permitting of the automatic moving of said contact member to off-position and retaining it there independently of any movement of said opposed push buttons.

13. An electrical snap switch comprising opposed push buttons, a contact member normallymovable into on-and-ofi' positions by actuating said push buttons, and a fusible e ement controlling the normal operation of said contact member through the agency of said push buttons, said fusible element when raised to an abnormally high temperature permitting of the moving of said contact member to off-position and discontinuing operative connection between said contact member and said opposed push buttons.

14. An electric switch comprising opposed push buttons, a movable contact member, a spring for normally actuating said contact member by means of said push buttons, heat responsive means, and a connection between said heat responsivemeans and said opposed push buttons to retain the tension in said spring, said connection being released to move said contact member into off-position when the heat responsive means assumes an abnormally high temperature.

15. An electric switch comprising opposed push buttons, a movable contact member,-a spring normally connecting said contact member to said push buttons, a resoldering element, and a connection between said resoldering element and said contact member for operatively connecting the contact member to said opposed pushbuttons, said con nection being automatically released when tact member from operative connection with said push buttons.

"17. An electric switch comprising a movable contact member, opposed push buttons for normally moving said movable contact member to oif-and-on positions, heat responsive means operatively connecting said movable contact member to said push buttons, and means automatically disconnecting said movable contact member from operative connection with said push buttons when said heat responsive means is overheated.

18. An electric switch comprising a movable contact member, opposed push buttons for normally moving said movable contact member to ofi-and-onpositions, heat responsive means operatively connecting said movable contact member to said push buttons, and means automatically disconnecting said movable contact member from operative connection with said push buttons during thetime only when such heat responsive means is overheated.

19. An electric switch comprising a movable contact member, opposed push buttons for normally moving said movable contact member to ofi-and-on positions, heat responsive means operatively connecting said movable contact member to said push buttons, and

means automatically disconnecting said movable contact member from operative connection with said push buttons and precluding resetting of said contact member in on-position when said heat responsive means is abnormally heated.

20. An electrical switching mechanism comprising astationary contact member, a movable contact member, a spring element, a fusible element, and a latching member operably associated therewith, said fusible element when in its normal state holding said spring element under tension when said movable contact member is in closed position or open position but allowing said movable contact member to move to open position under the action of said spring when said fusible element is in an abnormal state which causes the latching from its normal position.

21. An electrical switching mechanism comprising a stationary contact member, a movable contact member, a lever, a spring element operabl associated with said lever and said mova le contact member, a resoldering element, a latching member connecting said resoldering element to said lemember to move ver, and manually operated means for moving said movable contact member to open or closed position in opposition to the tension exerted by said spring element, said resoldering element when unduly heated releasing said latching member whereby said spring ma lose its tension thereby moving said mova 1e contact member to open POSI- tion, said resolderin element allowing operative connection etween said latchin member and lever to be restored when said resoldering element becomes cooled.

In witness whereof, I have hereunto subscribed my name.

JOHN s. BAKER. 

